Maybe it's because the exchange listing fees are very expensive or because they want to focus first on developing the platform. Even though they have been listed on many exchanges but there is no guarantee Moac price will grow fast, so in my opinion this is the right decision.
Yea getting listed on an exchange is tricky and expensive. Looks like MOAC is working on case studies. They recently launched their first app Moodata. They even had a webinar showing people how easy it is to launch a dapp:
https://www.moac.io/newmoodada.html